An “eye diagram” may depict a transmitter output of a serial bus. Data that is generated from a register file, RAM (random access memory), or linear feedback shift register is sent through the transmitter. The output of the transmitter is characterized over time and voltage by taking multiple samples at each time/voltage point. Known methods require that output data be compared to input data, and thus are not independent on logic and line delays.
It is therefore a drawback of the prior art that output data must be compared to input data, and that they are subjected to logic and line delays.